Multicylinder magneto



March 2, 1943. w sc w Rz ETAL I 2,312,447

MULTIGYLINDER MAGNETO 2 Sheets-Sheet l INVENTORS Filed larch 3, 1942 Mar2, 1943- W/E. SCHWARZMANN arm. 2,312,447

MULTICYLINDER MAGNETOV Filed March a, 1942 2 Sheets-Sheet 2 LAM/ Q5411ATTORNEY Patented Mar. 2, 1943 MULTICYLINDER MAGNETO Wolfgang E.Schwarzmann, Longmeadow, and Frank S. Coe, Springfield, Mass, and LeonW. Rosenthal, New York, N. Y., assignors to American Bosch Corporation,Springfield, Mass, a

corporation of New York Application March 3, 1942, Serial No. 433,114

16 Claims.

This invention relates to multicylinder magnetos of the inductor typefor electrical ignition for internal combustion engines, and moreparticularly to a magneto incorporating a stationary coil or coils anddistributor mechanism for the sparkplugs of the engine but having nogearing between the distributor mechanism and the generator rotor, asfor instance a magneto adapted to be driven at engine cam shaft speed.

In magnetos of this general type, herein termed multicylinder magnetosof the gearless inductor type, it has been customary to arrange the coilassociated with the generator rotor on the same side of both theinterrupter and distributor mechanisms, the generator rotor and coilbeing near one end of the rotor shaft as the bottom thereof, and theinterrupter and distributor mechanisms being near the other end of therotor shaft as the top thereof. For instance, in U. S. Patent 2,116,353the distributor is arranged between the interrupter mechanism and thecoil, and in U. S. Patents 1,993,824, 2,130,316 and 2,243,416, theinterrupter mechanism is arranged between the distributor mechanism andthe coil. In U. S. Patent 1,693,345, the generator rotor is likewisebelow the interrupter and distributor mechanisms but the coil is abovethem. In all these instances, either there is difficulty in maintainingthe primary and secondary connections of the ignition coil separate fromeach other, and also hazards in operation due to electrical breakdownbetween the connections or to the grounded frame particularly in hightension magnetos of this type, or else one of the connections isrelatively long and extends through a tunnel in the magneto frame oroutside the magneto or as an insert through the distributor plate orcap. Furthermore, it is difiicult if not impossible in these priorarrangements to fasten the stationary distributor member for thesparkplugs to the ignition manifold and/or to the engine frame and atthe same time to provide for the ready removal and exposure of therotatable and other internal parts of the magneto for purposes ofinspection, adjustment, repair and replacement thereof.

In accordance with the invention, the ignition coil of the magneto isarranged between those parts of the interrupter and distributormechanisms to which the coil is electrically connected, whereby a shortprimary conductor from the coil extends in one direction to theinterrupter mechanism in proximity thereto and preferably near the topof the rotor shaft, and a short secondary conductor from the coilextends in the opposite direction to the distributor mechanism also inproximity thereto and preferably near the other end of the rotor shaft.In this way, the primary and secondary connecting wires, which in thecase of a high tension magneto are respectively the low and high tensionwires, are separated from each other and both are of minimum length,whereby the likelihood of electrical breakdown between them and to thegrounded frame is reduced. Furthermore, the stationary distributormember to which the sparkplug wires are connected may then be combinedwith the ignition manifold and thereby considerably simplify and improvethe mechanical and electrical connections between the two and to thesparkplugs, and preferably may then be arranged at that end of thegenerator shaft which is coupled to the engine drive shaft and in factmay be fastened to the engine frame. Preferably also, the generatorrotor associated with the coil is mounted on the rotor shaft between theinterrupter cam and the distributor rotor thereon, to thereby furthersimplify and compact the structure and the electrical connections. Also,in the manner hereinafter disclosed, this arrangement provides, asdesired whenever the engine is at rest, for readily removing from themagneto frame the rotor shaft, generator rotor and coil, the interruptermechanism, and the distributor rotor, together with the remainder of thegenerator stator structure, which thereby permits the servicing thereof.

Accordingly the primary object of the invention is to provide amulticylinder magneto of the gearless inductor type which is simple andcompact in construction and arrangement, which is free from some of thecauses of electrical breakdown in prior magnetos of this type, whichalso provides for readier disassembly for inspection, adjustment, repairand replacement, and which provides if desired for permanent andimproved electrical and mechanical connections between the magneto andthe ignition manifold and with the engine fi .me.

These and other objects and advantages of the invention will be obviousfrom the following disclosure taken in conjunction with the accompanyingdrawings, which, as an example, refer to a multicylinder high tensiondouble magneto of this gearless inductor type for simultaneously firingtwo sparkplugs in each cylinder of a multicylinder aviation engine ofthe four-stroke cycle type. In the drawings,

' Fig. 1 is a central vertical section, partly in elevation and partlybroken away, of a magneto of this kind representing the preferredembodiment of the invention with the stationary distributor memberfastened to the ignition manifold and to the engine frame; Fig. 2 is avertical section, partly in elevation, showing the mounting of theignition coils in the stator structure; and Fig. 3 is an elevation ofthe stator structure of Fig. 2.

The frame of the magneto is of non-magnetic material as die castaluminum or zinc alloy and comprises a distributor housing section Iadapted to be fastened by screws as 2 to the engine frame 3, and agenerator and interrupter housing section 4 fastened to an uppernon-magnetic supporting member 5 of the magneto stator structure byscrews as S, the cap I of the interrupter housing being fastened inplace by screws as 8. The lower part 9 of the supporting member isfastened by screws as H] to the housing section I, and this section hasa cable outlet I I which is coupled in the well known way to an ignitionmanifold I2 which contains the sparkplug cables I3 between the magnetoand the engine cylinders and completes the electrostatic shield for theignition system.

The magneto has a rotor shaft I4 mounted in an upper ball bearing I5carried by a bearing support I6 fastened by screws as I! to member 5 andalso mounted in a lower ball bearing I8 of the separable type carried bya support I9 in frame section I, the rotor shaft being connected to thecam shaft of the engine 3, in timed relation thereto, by an adjustabledrive coupling 20 of any suitable kind. Near the lower end of shaft I4and fastened thereon, is a multicylinder distributor mechanismcomprising two distributor rotors 2I, 22 having continuous metal rings23, 24 and distributor electrodes 25, 23 which cooperate sequentiallywith respective circularly-disposed stationary electrodes 21, 28 ininsulator rings 29, 3D dowelled together as at 3I and to the frame as at32.

Fastened on the upper end of shaft I4 are superposed multilobe ormulticylinder cams 34, and fastened in adjusted angular position onmember 5 is an interrupter plate 35. On the plate are mounted twointerrupters 35, 3! of well known kind having cam followers 38, 39cooperative with the respective cams to periodically and simultaneouslyseparate the sets of contact points 45, 4I. shunted by respectivecondensers 42, 43 and the interrupters have respective live terminals44. 45.

Fastened on the shaft I4, between the distributor rotors 2I, 22 and thecams 33, 34 is a magnetic rotor 45 of laminated sheet steel with radialprojections of the proper number and angular extent, as is well known.This magnetic rotor cooperates with the stator structure includingmagnets 41, 48, laminated pole shoes 49, 50, 5|, 52 and the ignitioncoils 53, 54 with laminated cores 55 56 fastened across respective setsof pole shoes so as to simultaneously generate ignition voltages inthose coils in the well known manner. The coils have low tensionwindings with live terminals as 51 and high tension windings with liveterminals 58, 59. The primary coil terminals are connected to therespective interrupter terminals 44, 45 by wires 50, 6| passing throughthe supporting member 5, and the secondary terminals 58, 59 areconnected to the respective distributor rotors 2|, 22 by the insulatedconnectors 62, 63 which are mechanically fastened to the member 9 andelectrica ly connected to the respective rings 23, 24 by spark gaps.

The two distributor rotors 2 I, 22 with their re- These contact pointsare spective distributor rings 29, 30 constitute a distributingmechanism arranged near the bottom of the rotor shaft I4, and the twointerrupter cams 33, 34 with their cooperative interrupters 36, 3!constitute an interrupter mechanism arranged near the top end of therotor shaft. The magnetic rotor 44 with the stator structure includingthe magnets, pole shoes and ignition coils constitute a generatormechanism and this is arranged between the interrupter and distributormechanisms. By this arrangement, the primary connections or 6| and thesecondary connections 62 or 63, for each coil, extend in oppositedirections to the interrupter and distributor mechanisms respectively,and thereby are relatively short and are kept apart from each otherwithout any of them extending through a tunnel in the frame or on theoutside of the magneto, but directly between proximate terminals withreduced likelihood of electrical breakdown at any place of anyconnection. Furthermore, the comparatively short primary connections 60,6| contribute in some measure to the effective generation of ignitionvoltages. Also, by this arrangement, the distributor mechanism islocated at the bottom end of the magneto so that the distributor rings29, 30 may be fastened in the bottom housing section I which in turn isfastened to the ignition manifold I2 and to the engine frame 3, so thatthese parts may remain fastened to the engine without being disturbedwhile the other internal parts of the magneto are removed, ashereinafter described, for the purpose of inspection, adjustment, repairand replacement.

Practically all the internal and operative parts of the magneto may beremoved from the housing sections without detaching or disturbing thestationary distributor members or their electrical connections to thesparkplug cables in the ignition manifold I2, or their mechanical connection to the housing section I or its connection to the engine frame 3or the ignition manifold. By loosening the screws 8, the cap I may beremoved, as indicated in broken lines in Fig. 1, for inspection,adjustment, repair and replacement of the interrupter mechanism, andalso to provide access to the screws 6. Upon removing those screws 6,the housing section 4 may be removed, also as indicated in broken linesin Fig. l. to inspect and sometimes service the coils 53, 54 and theirmechanical and electrical connections in the stator structure of themagneto, and also to provide access to the screws I8. Upon removal ofthose screws I0, and the disconnection of the drive coupling 20, theinterrupter and generating mechanisms and the distributor rotors,together with all the electrical connections therebetween, may beremoved as a unit from the housing section I and the therein-containedstationary distributor members 29, 30, the bearing I8 being separablefor this purpose. All parts of that unit may then be serviced at anytime that the engine is at rest. If desired, the distributor member 29,30 may then be mechanically and electrically disconnected from thehousing section I and from the sparkplug cables in the ignition manifoldI2, and then upon removal of the screws 2 the housing section I may beremoved from the engine after being mechanically disconnected from theignition manifold.

While but one embodiment is her in disclosed, it will be obvious thatvarious parts of the invention may be applied to many forms ofmulticylinder magnetos of the gearless inductor type,

and that many modifications may be made. For

instance, a single magneto may otherwise have some or all the featuresdisclosed, ignition for multicylinder engines having any number ofcylinders may be provided, the interrupter and distributor mechanismsmay be transposed in location with respect to the ignition coil or coilsbetween them, the stationary distributor member need not be incorporatedwith the ignition manifold and neither one nor both need be fastened tothe engine frame, the engine with which the magneto is associated may beof the two-stroke or other suitable cycle, the magneto frame need not bephysically divided into the number of parts or the arrangementdisclosed, the permanent magnet may be mounted on the generator rotorinstead of being incorporated in the stator structure and that rotor maybe mounted on the shaft in a place other than between the interruptercam and the distributor rotor so long as the ignition coil is betweenthe interrupter and distributor mechanisms, the two interrupter cams fora double magneto may be replaced by a single cam for the two sets ofcontact points, and the interrupter and the distributor mechanisms for asingle or double magneto may be of other suitable type. These and othermodifications are intended to be included within the broadinterpretation of the terms of the appended claims.

Havin 'thus described the invention, what is claimed is:

1. In a multicylinder magneto of the gearless inductortype, a rotorshaft adapted to be driven by an engine, interrupter mechanism includinga multicylinder cam mounted on the shaftand also electrical contactscooperative therewith, multicylinder distributor mechanism including adistributor rotor electrode mounted on the shaft and also including astationary member with electrodesin circular arrangement about the shaftin cooperation with the rotor electrode, and generator mechanismincluding a magnetic rotor mounted on the shaft and also a stationarycoil which is located between the contacts of the interrupter mechanismand the rotor of the distribut-or mechanism and which has a primaryconnection extending in one direction to the interrupter contacts and asecondary connection extending in the opposite direction to thedistributor rotor electrode.

2. In a multicylinder magneto of the gearless inductor type, a rotorshaft adapted to be driven and generator mechanism which includes amagnetic rotor mounted on the shaft between the interrupter cam and thedistributor rotor electrode and which also includes a stationary coilhaving a primary connection extending in one direction to theinterrupter mechanism and a secondary connection extending in theopposite direction to the distributor mechanism.

4. In a multicylinder magneto of the gearless inductor type, a rotorshaft adapted to be driven by an engine, interrupter mechanism includinga multicylinder cam mounted on the shaft and electrical contactscooperative therewith, multicylinder distributor mechanism including arotor electrode mounted on the shaft and a stationary member withelectrodes in circular arrangement about the shaft in cooperation withthe rotor electrode, and a generator mechanism which includes a magneticrotor mounted on the shaft between the interrupter cam and thedistributor rotor electrode and which also includes a stationary coilmounted between the interrupter and distributor mechanisms incooperation with the magnetic rotor and having a primary connectionextending in one direction to the interrupter contacts and a secondaryconnection extending in the opposite direction to the distributor rotorelectrode.

5. In a multicylinder double magneto of the gearless inductor type, arotor shaft adapted tobe driven by an engine, interrupter mechanismincluding two sets of electrical contacts incooperation withmulticylinder cam means mounted on the shaft, multicylinder distributormechanism including two stationary sets of electrodes each in circulararrangement about the shaft and also including two rotor electrodesmounted on the shaft in cooperation with the electrode setsrespectively, and generator mechanism which includes a magnetic rotormounted on the shaft between the cam means and the distributor rotorelectrodes and which also includes two stationary coils mounted betweenthe interrupter and distributor mechanisms in cooperation with themagnetic rotor, each coil having a primary connection extending in onedirection to a respective set of interrupter contacts and a secondaryconnection extending in the opposite direction to a respectivedistributor multicylinder cam mounted near that end of the shaft,multicylinder distributor mechanism which is arranged near the other endof the shaft and mounted on the shaft and also a stationary coil havinga primary connection extending in one direction to the interruptermechanism and a secondary connection extending in the opposite directionto the distributor mechanism. 7

3. In a multicylinder magneto of the gearless inductor type, a rotorshaft adapted to be driven by an engine, interrupter mechanism includinga multicylinder cam mounted on the shaft near one end thereof,multicylinder distributor mechanism including a rotor electrode mountedon the shaft near the other end thereof and also including stationaryelectrodes in circular arrangement about the shaft in cooperation withthe rotor electrode,

which includes a rotor electrode mounted on the shaft and also 'astationary member mounted in the frame and having electrodes in circulararrangement about the shaft in cooperation with the distributor rotorelectrode, and generating mechanism which is located between theinterrupter and distributor mechanisms and which includes a magneticrotor mounted on the shaft and also a stationary coil having aprimaryconnection extending in one direction to the interrupter mechanism and asecondary connection extendin in the opposite direction to thedistributor rotor electrode.

7. In a multicylinder magneto of the gearless inductor type, a framehaving an interrupter housing, a rotor shaft adapted to be driven by anengine and extending into the interrupter housing. generator mechanismwhich includes a magnetic rotor mounted on the shaft and which alsostructure between the interrupter and distributor mechanisms and havinga primary connection expied to an engine, distributor mechanism whichtending in one direction to the electricalcont'acts and a secondaryconnection extending in the opposite direction to the distributor rotorelectrode.

8. In a multicylinder magneto of the gearless inductor type, a framehaving an interrupter housing section at the top, a rotor shaftJournaled in the frame and adapted to be driven by an engine, generatormechanism including a magnetic rotor mounted on the shaft and alsoincluding a stator structure having a coil and a supporting member whichis detachably fastened to the frame for supporting the stator structuretherein and in which the rotor shaft is journaled also, interruptermechanism which is arranged in the inincludes a rotor mounted on theshaft and which also includes a stationary member having electrodesarranged in cooperation with the distributor rotor, interruptermechanism which includes a cam mounted on the shaft and which alsoincludes interrupter contacts arranged in cooperation with the cam,generator mechanism which includes a magnetic rotor mounted on the shaftand which also includes a stator structure having a coil electricallyconnected to the distributor rotor and to the interrupter contacts andalso having a supporting member supporting the interrupter contacts, asectionalized frame which has one section housing. the stationarydistributor member and adapted to be detachably fastened to the engineand to the supporting member and which also has another section housingthe generator and interrupter mechanisms and being detachably fastenedto the supporting member,

.said shaft being journaled in the distributor terruptr housing andwhich includes a cam mounted on the shaft and electrical contactsmounted on the supporting member in cooperation with the cam, anddistributor mechanism which includes a rotor mounted on the shaft andwhich also includes a stationary member fastened housing section of theframe and also-being journaled in and supported by the supportingmember, whereby, upon detaching the supporting member from both sectionsof the frame, the rotor shaft with the parts mounted thereon togetherwith thestator. structur ir'nd interrupter mechanism may be removed as aunit from the stationary distributor member.

11. In a multicylinder magneto of the gearless inductor type, a rotorshaft adapted to be coupled to the frame near the bottom thereof andhaving electrodes arranged in cooperation with the distributor rotor,the coil being arranged in the stator structure between the interrupterand distributor mechanisms and having a primary'connection extending inone direction to the electrical contacts and a secondary connectionextending in the "opposite direction to the distributor rotor.

9. In a multicylinder magneto of the gearless inductor type, asectionalized frame which has a lower distributor housing sectionadapted to be fastened to an engine and which also has an uppergenerator and interrupter housing section with a detachable cap on itstop, a rotor shaft iournaled in the lower section and adapted to bedriven by the engine, generator mechanism in cluding a magnetic rotor onthe shaft and also including a stator structure having a coil and asupporting member in which the rotor shaft is journaied also,interrupter mechanism which is arranged in the interrupter housing andwhich includes a cam mounted on the shaft and electrical contactsmounted on the supporting mem-' her in cooperation with the cam, anddistributor mechanism which includes a rotor mounted on the shaft andwhich also includes a stationary member fastened to the lower framesection and having electrodes arranged in cooperation with thedistributor rotor, the coil being arranged in tributor rotor, and thesupporting member being detachably fastened to both sections of the toan engine, distributor mechanism which includes a rotor mounted on theshaft and which also includes a stationary member having electrodesarranged in cooperation with the distributor rotor, interruptermechanism which includes a cam mounted on the shaft and which alsoincludes interrupter contacts arranged in cooperation with the cam,generator mechanism which includes a magnetic rotor mounted on the shaftand which also includes a stator structure having a coil electricallyconnected to the distributor rotor and to the interrupter contacts andalso having a supporting member supporting the interrupter contacts, asectionalized frame which has a lower section fastened to the stationarydistributor member and adapted to be fastened to the engine and whichalso has an upper section housing the generator and interruptermechanisms and having a detachable cap, said shaft being journaled inthe lower section of the frame and also being journaled in and supportedby the supporting member, and the supporting member being detachablyfastened to the upper section of the frame beneath the interrupter capand also being detachably fastened to the lower section of the frame,whereby upon removing the cap the supporting member may be detached fromthe upper housing section and then from tributor mechanismassociatedwith the shaft,

interrupter mechanism, associated with the shaft, and generatormechanism which is arranged between the distributor and interruptermecha- 2,312,447 mama and which includes a magnetic rotor mounted on theshaft and a stator structure cooperative with the magnetic rotor, saidstator structure comprising magnetic members, an ignition coil fastenedto' the magnetic members and electrically connected to the distributorand interrupter mechanisms, and a supporting member fastened to themagnetic members and to the frame for fastening the stator structuretherein and having a bearing for the rotor shaft.

13. In a multicylinder magneto ofthe gearless inductor type, a rotorshaft adapted to be coupled to an engine, distributor mechanismassociated with the shaft, interrupter mechanism associated with theshaft, generator mechanism which is arranged between the distributor andinterrupter mechanisms and which includes a magnetic rotor mounted onthe shaft and a stator structure cooperative with the magnetic rotor,and a frame for the magneto, said stator structure comprising magneticmembers, an ignition coll fastened to the magnetic members andelectrically connected to the distributor and interrupter mechanisms,and a supporting member fastened to the magnetic members and also to theframe for fastening the stator structure therein, and said rotor shaftbeing Journaled in the frame and in the supporting member.

14. In a multicylinder magneto of the gearless inductor type, a framefor the magneto, a rotor shaft adapted to be coupled to anengine,distributor mechanism associated with the shaft,

interrupter mechanism including a cam mounted on the shaft and alsointerrupter contacts, and generator mechanism which is arranged betweenthe distributor and interrupter mechanisms and which includes a magneticrotor mounted on the shaft and a stator structure cooperative with themagnetic rotor, said stator structure comprising magnetic members, anignition coil fastened to the'magnetic members and electricallyconnected to the distributor mechanism and also to the interruptercontacts, and a supporting member which is fastened to the magneticmembers and to the frame for fastening the stator structure therein andwhich also supports the interrupter contacts in cooperation with thecam.

15. In a multicylinder magneto of the gearless inductor type; a framefor the magneto, a rotor shaft adapted to be coupled to an engine;distributor mechanism including a rotor mounted on the shaft and also astationary member having electrodes arranged in cooperation with thedistributor rotor; interrupter mechanism associated with the shaft;generator mechanism which is arranged between the distributor andinterrupter mechanisms and which includes a magnetic rotor mounted onthe shaft and a stator structure cooperative with the magnetic rotor;said stator structure comprising magnetic members, an ignition coilfastened to the magnetic members and electrically connected to theinterrupter mechanism, and a supporting member fastened to the magneticmembers and also to the frame for fastening the stator structuretherein; and an electrical connector which is fastened to the supportingmember and which electrically connects the ignition coil to thedistributor rotor. I 16. In a multicylinder magneto of the gearlessinductor type; a frame for the magneto, a rotor shaft adapted to becoupled to an engine; distributor mechanism associated with the shaft,interrupter mechanism including a cam mounted on the shaft and alsointerrupter contacts; generator mechanism which is arranged between thedistributor and interrupter mechanisms and which includes amagnetic-rotor mounted on the shaft and a stator structure cooperativewith the magnetic rotor; said stator structure comprising magneticmembers, an ignition coil fastened to the magnetic members andelectrically connected to the distributor mechanism, and a supportingmember which is fastened to the magnetic members and also to the framefor fastening the stator structure therein and which supports theinterrupter contacts in cooperation with the cam; and an electricalconductor passing through the supporting member and electricallyconnecting the ignition coil with the interrupter contacts.

WOLFGANG E. SCHWARZMANN. FRANK S. COE. LEON W. ROSENTHAL.

